Precision small wire and untwisting tool

ABSTRACT

A multi-purpose hand tool for use with fine gauge insulated wire. The hand tool can be used to cut wire, to cut and strip insulation from wire and to untwist twisted pairs of wire. The insulation cutting and stripping portion of the tool has an alignment guide for the wire which floats relative to the cutting blade for accuracy of alignment of the wire with the insulation stripping aperture. The wire untwisting means includes plastic pads carried by the tool members and movable into closely spaced relationship with each other upon closing of the tool to engage and straighten the wires of a twisted pair of wires pulled between the pads.

This application is a division of Ser. No. 610,537, filed Sept. 5, 1975now U.S. Pat. No. 4,047,297, isued Sept. 15, 1977.

SUMMARY OF THE INVENTION

This invention is concerned with a precision hand tool useful forcutting and stripping the insulation of an insulated wire, foruntwisting a pair of twisted wires and for cutting insulated wires. Itis particularly concerned with such a multi-purpose tool for use withfine gauge insulated wire.

An object of this invention is a hand tool having means for cutting andstripping the insulation of an insulated wire of fine gauge withoutnicking the wire.

Another object of this invention is a hand tool having insulationstripping means for fine gauge wire in which the wire is aligned withthe insulation cutting blade by a floating wire guide.

Another object is a tool having means for untwisting a twisted pair offine gauge wires.

Another object is a hand tool having wire untwisting means consisting ofa pair of plastic pads that engage and straighten the wires of a twistedpair of wires pulled between the pads.

Another object is a precision hand tool capable of simultaneouslystripping a pair of fine gauge insulated wires.

Other objects may be found in the following specification, claims anddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated more or less diagrammatically in thefollowing drawings wherein:

FIG. 1 is a front elevational view on an enlarged scale of a toolembodying the novel features of this invention;

FIG. 2 is a side view of the tool of FIG. 1 with portions shown incross-section; FIG. 3 is a partial view of the reverse side of the toolthat shown in FIG. 1;

FIG. 4 is a partial rear elevational view of a modified form of tool;

FIG. 5 is a plan view of a modified form of wire guide; and

FIG. 6 is a cross-sectional view taken along lines 6--6 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 of the drawings shows a hand held tool 11 which may be used forcutting and stripping insulation from wire of fine gauge. The tool isespecially useful in stripping insulation of synthetic plastic which isextremely tough and difficult to cut. The tool includes two elongatedmembers 13 of almost identical construction. Conveniently, these membersmay be metal stampings. Each elongated member includes a handle portion15 and a wire cutting blade portion 17. The blade portion of each memberis offset both from the axis of the handle portion and laterally fromthe plane of the handle portion. The offset of the blade portion fromthe plane of the handle portion is equal to one half the thickness ofthe handle portion so that the blade portions are flush with each otherwhen the handle portions are aligned as shown in FIG. 2. The elongatedmembers 13 are pivotally connected by a rivet 19 extending throughopenings (not shown) formed in the offset portions of the members. Eachwire cutting blade portion includes an arcuate slot 21 and a projectingpin 23 each located on opposite sides of the rivet opening. The pin 23may be force fitted into a suitable hole (not shown) formed in themember. The projecting pin of one member fits into the slot of the othermember with the pin and slot forming stop means to limit opening pivotalmovement of the elongated members 13 relative to each other.

A projection 27 is formed on an edge of each handle portion. Theseprojections are similarly located on each handle portion so that theymove into contact with one another when the handles are pivotally movedtogether. A semi-cylindrical groove 29 is formed at the contacting edgesof each projection. The groove 29 extends partially through thethickness of the handle portion 15. The groove terminates in asemi-cylindrical cutting edge 31. The groove and cutting edge may beformed by drilling through the handle portion so that only the tip ofthe drill extends out of the handle portion. In order for the cuttingedges 31 on the pair of handle portions to be located on the same sideof the tool, it is necessary for the grooves to be drilled from oppositesides of each of the handle portions.

When the projections 27 come together upon actuation of the tool, thesemi-cylindrical grooves 29 and cutting edges 31 form an insulationsupporting tube and insulating cutting element having an aperture. Thecutting aperture has a diameter no less than the diameter of the coreportion of the wire to be stripped and the insulation supporting tubehas a diameter no less than the outside diameter of the insulationjacket of the wire.

A wire alignment guide 41 formed of a suitable plastic such as nylon ismounted on the insulation cutter edge side of the tool. The wirealignment guide includes an elongated rectangular base 43 which extendsbetween the handle portions 15. Stubs 45 formed on the base extendthrough arcuate slots 47 formed in the handle portions 15. Spring likelocking grippers 49 fit over the stubs and hold the wire alignment guidein position on the tool. The opposite side of the base 43 from the stubshas an upstanding cylindrical projection 51 formed thereon. An opening53 extends axially through this projection and the base. The opening hasa funnel shaped entrance 55 which merges with a cylindrical passage 57.The cylindrical passage has a diameter substantially equal to theoutside diameter of the insulation of the wire to be stripped.

The arcuate slots 47 in which the wire alignment guide rides are locatedon the same circle as the semi-cylindrical grooves 29 and cutting edges31. The slots are formed so that the ends of the slots will contact thestubs 45 of the wire alignment guide to center the cylindrical passage57 of the guide with the cutting aperture as the projections 27 contacteach other.

A pair of wire untwisting pads 61 are mounted on projections formed onthe handle portions 15 adjacent to the projections 27. The pads 61 areformed of a suitable relatively soft plastic such as nylon and are ofidentical construction. Each has an outwardly extending portion 63 atone end thereof which overlaps the other pad 61 when the handle portionsare moved together upon closing movement of the tool. The faces 65 ofthe pads are moved close to but not in contact with each other uponclosing of the tool. The pads may be closed on a pair of twisted wiresto thereby form a restricted passage for the wires.

A compression spring 69 fits over projections 71 formed on the handleportions 15 to bias the handle portions away from each other. Insulatingsheaths 73 fit over the handle portions outwardly of the compressionspring 69. The insulating material may be vinyl or other suitablematerial.

A modified form of wire alignment guide and insulation cutting andstripping projections is shown in FIGS. 5 and 6 of the drawings. Themodified guide and cutting projections are provided to simultaneouslystrip two wires. The modified alignment guide 81 is formed of a suitableplastic and includes a base 83, stubs 85 to opposite ends of the basewhich extend through the arcuate slots 47 formed in the handle portions15 of the tool 11. Locking members 49 fit over the stubs to hold thewire alignment guide 81 in position of the cutting tool. The wirealignment guide has a generally cylindrical upstanding projection 87formed on the base 83 on the side opposite to the stubs 85. A pair ofopenings 89 extend axially through the projection and the base 83. Eachopening has a funnel shaped entrance 91 which connects with acylindrical passage 93. The diameter of the cylindrical passage 93 isapproximately equal to the outside diameter of the insulation of thewire to be stripped.

The projections 101 formed on the handle portions 15 each have a pair ofspaced semi-cylindrical grooves 103 with each groove having asemi-cylindrical cutting edge at one end thereof. When the projections101 are brought together, the grooves 103 formed insulation supportingtubes and insulation cutting apertures. Whereas in this example, thesemi-cylindrical grooves and cutting edges are of the same diameter, aswould be necessary for cutting both strands of the twisted pair ofwires, it should be understood that these grooves and cutting edgescould be of different diameters for use with wires of differentdiameters.

The use, operation and function of this invention are as follows:

The multi-purpose hand tool 11 of this invention is intended for usewith fine gauge insulated wire of the type commonly used in electronicdevices. Wire of this type ranges in size from 18 to 32 A.W.G. andsmaller. The wire core in usually covered with a synthetic plasticinsulation. This insulation is very thin and very tough and isexceedingly difficult to remove without nicking the wire core. Thesewires frequently are found in twisted pairs, especially in electroniccommunication devices.

The blades 17 of this multi-purpose tool are used to cut wire. Theseblades, which are shown as having a 90° cutting angle as would beobtained from a stamping, may also be provided with a tapered cuttingedge. In addition to use in cutting, the tool of this invention may alsobe used for stripping insulation from the ends of wires. The end of thewire to be stripped is inserted into the funnel shaped entrance 55 ofthe wire alignment guide 41. The wire is pushed through the guide sothat it extends between the insulation cutting blades or projections 27formed on the handle portions 15 of the elongated members 13. The movingtogether of the handle portions 15 of the tool will force the wirealignment guide 41 into alignment with the semi-cylindrical cuttingedges 31 of the insulation cutting blades. The semi-cylindrical grooves29 formed in the projections 27 are also centered upon and engage theinsulation covering the wire thereby providing support for the insulatedwire while the insulation is being cut by the cutting edges 31. Thecutting edges 31 cut through the insulation but stop short of the coreof the wire. With the handle portions 15 held together, the insulationis stripped from the wire by moving the tool relative to the wire.

The modified form of tool shown in FIGS. 4, 5 and 6 of the drawings maybe used to simultaneously strip insulation from both wires of a pair ofwires. Additionally, the wire stripping cutting elements 103 may be ofdifferent sizes so that wires of different diameters may be strippedeither simultaneously and individually.

The tool of this invention may also be used for untwisting pairs oftwisted wires. The wires are untwisted by inserting them between thewires untwisting pads 61 which are formed of a soft plastic such asnylon. When the wires are positioned between the pads, the handleportions 15 are moved together moving the pads towards each other andtrapping the pair of twisted wire between the faces 65 of the pads andthe overlapping portions 63 of the pads. With the faces 65 of the padsheld in close proximity of one another, the twisted wire is pulledbetween the pads. The pads engage the wires and tend to parallel thewires and untwist them.

The compression spring 69 urges the handle portions 15 apart whichcarries the blades 17 to their open position. The amount of opening ofthe blades is controlled by the stop members 23 which ride in the slots21 formed in the blade portions.

We claim:
 1. A tool for use with fine gauge insulated wire formed intwisted pairs, said tool including a pair of elongated members pivotallyconnected to each other, handles on one side of the pivot to providemanual manipulation for the tool, cutting blades on the elongatedmembers, and a wire untwisting device on the members including a plasticpad mounted on each elongated member on the inner surface thereof infacing relation to each other so upon pivotal movement of the elongatedmember the pads move toward and away from each other, an opposedsurfaces on each of the pads which close upon manipulation of theelongated members to form a guideway which engages the wires and causesthem to untwist when the wire is being pulled therethrough and thehandles are held with the opposed surfaces closely adjacent to eachother defining the guideway, and a first projecting means on one of thepads which, when the elongated members are in their open position, isspaced from the other pad to provide an opening so that the twistedwires may be inserted, and a second projecting means on one of the padsspaced from said first projecting means longitudinally therefrom andbeing substantially in the same plane of the pads, said first and secondprojecting means each extending from their respective pad to overlap theother pad so as to close the guideway at each end when the handles aremanipulated to the closed position.
 2. The structure of claim 1 furthercharacterized in that the cutting blades are on one side of the pivotand the plastic pad is on the other side.